Convert some audio code to OnceCallback.

content/browser/media/media_devices_permission_checker.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_MEDIA_MEDIA_DEVICES_PERMISSION_CHECKER_H_
 #define CONTENT_BROWSER_MEDIA_MEDIA_DEVICES_PERMISSION_CHECKER_H_
 
 #include <memory>
 
 #include "base/callback.h"
@@ skipping 29 matching lines @@
   // Checks if the origin |security_origin| associated to a render frame
   // identified by |render_process_id| and |render_frame_id| is allowed to
   // access the media device type |device_type|. The result is passed to
   // |callback|.
   // This method can be called on any thread. |callback| is fired on the same
   // thread this method is called on.
   void CheckPermission(MediaDeviceType device_type,
                        int render_process_id,
                        int render_frame_id,
                        const url::Origin& security_origin,
-                       const base::Callback<void(bool)>& callback) const;
+                       base::OnceCallback<void(bool)> callback) const;
 
   // Checks if the origin |security_origin| associated to a render frame
   // identified by |render_process_id| and |render_frame_id| is allowed to
   // access the media device types marked with a value of true in
   // |requested_device_types|. The result is passed to |callback|. The result is
   // indexed by MediaDeviceType. Entries in the result with a value of true for
   // requested  device types indicate that the frame has permission to access
   // devices of the corresponding types.
   // This method can be called on any thread. |callback| is fired on the same
   // thread this method is called on.
   void CheckPermissions(
       MediaDevicesManager::BoolDeviceTypes requested_device_types,
       int render_process_id,
       int render_frame_id,
       const url::Origin& security_origin,
-      const base::Callback<void(const MediaDevicesManager::BoolDeviceTypes&)>&
+      base::OnceCallback<void(const MediaDevicesManager::BoolDeviceTypes&)>
           callback) const;
 
  private:
   const bool use_override_;
   const bool override_value_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaDevicesPermissionChecker);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEDIA_MEDIA_DEVICES_PERMISSION_CHECKER_H_